author James Teh <>
Wed, 01 Feb 2023 05:02:01 +0000
changeset 651150 dd0fdd1daa69783be36acd5c50544f3694eaa8f9
parent 589289 7e795e95ddda3f9b8fb6fe4cff9077834f8b898e
permissions -rw-r--r--
Bug 1813980: Check IsDoc before Parent in RemoteAccessibleBase::ApplyCrossDocOffset. r=morgan We call this function on every ancestor when calculating bounds. RemoteParent() currently requires a hash lookup, so it's more efficient to early return for !IsDoc() first. This is a micro-optimisation, but it might have some impact given that we call this on every ancestor, especially when hit testing, where we call Bounds() a lot. As a bit of drive-by cleanup, use RemoteParent() rather than calling Parent() and IsRemote/AsRemote(). Differential Revision:

  <meta charset="utf-8">
  <meta name="viewport" content="width=2100"/>
  <title>Check that tall element wider than the viewport doesn't scroll to the top</title>
  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>
  <script type="application/javascript" src="apz_test_utils.js"></script>
  <script src="/tests/SimpleTest/paint_listener.js"></script>
  <script type="application/javascript">

// Although this test has hscrollable in the name, it does not test any
// horizontal scrolling. Rather it is the mere presence of horizontally
// scrollable content that triggers this bug (it confused the code that
// picked a rect to zoom to).

async function test() {
  let useTouchpad = ( == "?touchpad");

  let resolution = await getResolution();
  ok(resolution > 0,
     "The initial_resolution is " + resolution + ", which is some sane value");

  // instant scroll down
    top: window.innerHeight * 2,
    left: 0,
    behavior: 'auto'

  await promiseApzFlushedRepaints();

  let scrollPos = window.scrollY;
  ok(scrollPos > window.innerHeight * 2 - 50, "window scrolled down");

  info("window.scrollY " + window.scrollY);

  info("window.innerHeight " + window.innerHeight);

  info("document.documentElement.scrollHeight " + document.documentElement.scrollHeight);

  let target = document.getElementById("target");

  let x = 20;
  let y = scrollPos + window.innerHeight / 2;

  // Check that second double tap does not scroll up
  info("sending second double tap");
  await doubleTapOn(target, x, y, useTouchpad);
  prev_resolution = resolution;
  resolution = await getResolution();
  ok(resolution == prev_resolution, "After double-tap the resolution is the same: " + resolution);

  ok(window.scrollY > window.innerHeight * 2 - 50, "window is still scrolled down");
  ok(Math.abs(window.scrollY - scrollPos) < 1, "window didnt scroll");
  info("window.scrollY " + window.scrollY);

.then(subtestDone, subtestFailed);

    .spacer {
      background-color: #eee;
      height: 800vh;
      width: 200vw;
    .rect {
      width: 90vw;
      height: 30px;
      background-color: #aaa;
<div id="firsttarget" class="rect">

<div id="target" class="spacer">